Construction Of AFLP Molecular Markers Linkage Map In Peach (Prunus. Persica (L.) Bastch)

Peach is a kind of the perennial fruit crop. For it's long period of a generation, molecular genetic mapping is very important theoretically and practically in breeding. At present, the genetic linkage maps of peach that have already been published have some common problems such as the length of covering whole genome is short (most are only 50% or less) and the number of progeny is small, as well as some maps'average distance between adjacent loci are big(>10cM) especially that constructed by Chinese, even some markers can not integrated in maps.A linkage map of AFLPs was obtained using a F1 progency which were derived from a cross between nectarine cultivars'Qinguang2'and'Shuguang'with JoinMapâ—‹R 3.0 software. The main results as follows:DNA extraction method high-quality from mature leaves of peach was established: The stable and high efficient AFLP analysis system of peach-genome high quality of genome DNA was a critical step for AFLP analysis. Our method was based on the traditional way of CTAB and had some improvement slightly. The results showed: the extracted DNA of mature leaves by this method was pure, integral, the value of D260 nm/D280 nm was 1.80 to 2.0, degradation was nearly free, the RNA was eliminated completely, and suitable for digestion by restriction endonucleases, subsequent AFLP analysis was normal. Therefore this method could be used for extracting ideal DNA samples from mature leaves peach and suitable for AFLP.A higher-density genetic map was constructed: Polymorhism of parents was analysized with 120 pairs of AFLP primers. The selected 37 AFLP primers with rich and steady bands were tested in progeny. 158markers were scored, of which 27markers were skewed segregation. The amounts of locus derived from different parent were equal. No serious skewed segregation occurred. A linkage map was obtained using JoinMapâ—‹R 3.0 software's CP model. The map is composed of 122 AFLPs and two morphological traits(Y/y and F/f)distributed in 11 linkage groups, 36markers(containing 20 markers skewed segregation) were unlinked. The map covers 1034cM of the peach genome. The average length of linkage group is 94cM. Each group contains 2-23 loci, and the average distance between adjacent loci is 8.34. F/f was located in LG7, and linked to marker TC/CAA(300), the linkage distance was 10cM; Y/y was located in LG4 and linked to marker ACC/CTG(120)and CT/CTG(370), the linkage distance were 5.9cM and 12.6.From the mapping efficiency and the map's covering degree on the genome and the marker density, the linkage map constructed in this study was of enough quality and could be used to further research.